Many surgical therapies for functional mitral regurgitation (FMR) have been developed that treat the mitral valve (MV) annulus. Examples include the Carpentier ring annuloplasty and Kay annuloplasty procedures, which achieve annular reduction, and the Alfieri stitch, which coapts the MV leaflets using a suture. Percutaneous procedures have also been developed that adapt these surgical procedures to catheter based procedures. Each of these therapies treats only the symptoms of the underlying cardiomyopathy (e.g., mitral valve regurgitation) and not the cause (e.g., remodeling of the left ventricle).
It has been recognized that reducing the dilated left ventricle (LV) wall directly addresses the underlying cause of worsening FMR and heart failure (HF) symptoms by reducing preload and the effect of afterload—wall stress—on the LV.
Implants designed to cinch the LV free wall can also be used to address FMR. Examples include the tethered anchor implants described in U.S. Pat. Nos. 7,758,637 and 7,588,582. After gaining percutaneous access to the subvalvular space in the LV, the implant is placed against the endocardium using anchors that penetrate the myocardium and which are slidably coupled to a tether. Cinching the implant can reduce LV dimensions and volumes, improving MR status and LV function. The primary limitation to a percutaneous cinching approach in the LV is the diseased myocardium itself, which often is comprised of trabeculated (non-compacted) myocardium, post-MI scar tissue and weakened, friable myocardium. Such tissue is not well suited to withstand the loads induced by a cinched implant at the tissue-anchor interfaces.
Accordingly, there remains a need to provide a device and method to adequately place and cinch an implant into human myocardium, while not exceeding the strength of the diseased tissue.